There exists a vast array of imaging systems having a multitude of various constructions and compositions. Amongst the more widely used systems are silver halide light sensitive systems (including black and white and color photography, dry silver photothermography, instant photography, and diffusion transfer systems, amongst others), photopolymeric systems (including planographic and relief printing plates, photoresist etching systems, and imaging transfer systems), diazonium color coupling systems, and others. Each system has its own properties attributable to the phenomenon which forms the basis of the imaging technology. For example, silver halide imaging systems are noted both for amplification (i.e., image densities which can be increased by further development without additional imagewise exposure) due to the catalytic action of silver towards the reduction of silver ion and for the fact that light sensitivity may be stopped after development by washing away the light sensitive silver halide salt (i.e., fixing). Photopolymeric systems are noted for image stability and ease of application of the imaging layer. Diazonium color coupling systems have high image resolution and are easy to coat onto supporting substrates.
One other type of imaging system which has received some attention in recent years uses a salt comprising an aromatic tetra(hydrocarbyl) borate anion as a dye-bleaching or solubility-altering photosensitive compound. U.S. Pat. No. 3,567,453 discloses the use of such borate salts (having at least one aryl substituent on the borate) in photoresist and lithographic compositions. U.S. Pat. No. 3,754,921 discloses an imaging system comprising a leucophthalocyanine and "phenylboronate". U.S. Pat. No. 3,716,366 even indicates that image stabilization might be achieved by reaction or dissolution and removal of one of the components (column 5, lines 1-8). British Pat. Nos. 1,370,058; 1,370,059; 1,370,060; and 1,986,269 also disclose dye bleaching processes using aromatic borates as light sensitive agents.
U.S. Pat. No. 3,716,366 suggests that desensitization may be effected by reactions with one of the components to form stable colorless products, and specifically suggests selectively dissolving out one of the components. No specific reagents or reaction mechanisms are suggested for the desensitization process, however.